How nylon burns. Synthetic or natural cotton, which is better? How to distinguish cotton fabric from a synthetic fake? Burns without melting

Today we have laboratory work. Today we are setting fire to yarn. Not for the sake of self-indulgence, but for the sake of determining its composition. Experts call this process an organoleptic method for recognizing fiber by burning.

For what? Many years ago, you bought yarn, knitted something from it, and put the rest in long-term storage, forgetting to sign it. Or someone gave you yarn without labels, and you don’t know its composition. Or there may be some other situation, and the composition is also unknown. Is it necessary to at least roughly know what kind of animal is in your hands?

Is it necessary to know the composition of the yarn? Isn't it enough to visually and tactilely examine the thread and knit the product based on the thickness and color of the thread? No. The color and thickness are very insufficient.

Imagine, without knowing the composition of the yarn, you knitted a product, washed it and... The product stretched greatly in breadth or shrinked greatly. And if your summer T-shirt After washing it fluffed up a lot and resembles a shawl. Or your jumper has been welded so that its fabric has lost its pattern and resembles felt boots. These are not all the troubles that can happen due to a lack of understanding, what kind of yarn lies in front of you?

I suggest you at least roughly determine what you have to work with. Let's set fire to pieces of yarn. I remember we did this at school during home economics lessons, but there we burned fabric. The essence does not change today, since fabric and yarn are made in production from the same materials. So.

We take about 10 cm of yarn and set one end on fire. We look at how quickly the thread burns, what the color of the flame is and the nature of the combustion, pay attention to the smoke, if there is any. As soon as half of the thread has burned, we blow it out sharply and look at the result. As soon as everything has cooled down, we try to rub the combustion product with our fingers, that is, what remains after combustion.

Ball 1. The thread is badly eaten by moths. You don't have to burn it. The thread is natural, wool, quite edible and even very tasty. If the moth that found this ball died of gluttony without having time to leave offspring, you will not find it. Set fire to the thread. Wool doesn't melt. It burns slowly, the flame is weak and flickering, and the smoke smells like burnt feathers or hair. During combustion, black or dark brown ash appears in grains. The cooled grains crumble into powder. Chemists claim that wool is resistant to mineral acids, and is destroyed in hot sulfuric acid and weak alkali solutions.

Tangle 2. Silk. This is an animal fiber. It burns like wool, it smells the same, and when burned, its ash also forms in the form of a black ball, which also crumbles into powder. We are talking about natural silk. Rayon is a synthetic.

Tangle 3. Viscose. This fiber has a silky shine. Burns quickly and brightly, does not melt, smells of burnt wood or paper, leaves a light ash. Viscose dissolves in hot dilute and cold concentrated acids. Concentrated alkali solutions cause it to swell.

Tangle 4. Cotton. This vegetable fiber. It ignites easily, burns quickly with a bright yellow flame and has a burnt paper smell. When burned, it leaves a white-gray ash. Cotton is not very resistant to chemicals and minerals, mineral acids, but is resistant to alkalis.

Tangle 5. Linen. This is also a plant fiber, and when burned, it behaves in the same way as cotton, only it extinguishes faster and smolders poorly.

Tangle 6. Synthetics. There are a lot of synthetic fibers in production, and they all behave differently. Acrylic, nitron, acetate, nylon, nylon, polyester, spandex and a bunch of others with unearthly names - these are all synthetics. But they have a common property - they do not burn and do not leave ashes. They melt, leaving a dense ball. This is why firefighters and the Ministry of Emergency Situations do not recommend synthetic clothing. If the flame from natural clothing can be knocked down or extinguished, then the remnants of melting synthetic clothing stick to the body and leave burns. In addition, the smoke that is produced during combustion, that is, during melting, is often very poisonous. That is why in case of fires in large entertainment venues, where everything is decorated with plastic, people die not from fire, but from poisoning and suffocation. But not all synthetics stink so bad. For example, acrylic or melting reminds the smell of fish, acetate smells like vinegar and paper, nylon smells like celery. By the way, the color of the melted synthetic balls can also be different, creamy, bluish, and black. When hardened, these balls do not crumble into ashes, which distinguishes synthetic fibers from natural ones.

To summarize, we can say that fibers of plant origin (cotton, flax and everything that during their life represents grass and trees) when burned smell like burnt paper or wood, fibers of animal origin (wool, silk and everything that walks and eats during life) and makes sounds) when burning they smell like burnt feathers and hair, and fibers of synthetic origin, like all chemicals, can smell like anything and even stink like anything. The ash of fibers of plant and animal origin crumbles, and in most cases artificial ash is sintered into hard balls. I repeat: in most cases. This means that scientists do not stop there and the products of their creativity may soon give natural ones a head start, if they have not already.

Attention! These descriptions only apply to 100% yarn compositions. If the thread is a mixture of different fibers, it may be difficult to determine them, and even more so in their percentage composition. But here too you can fight.

Try to take the thread apart into pieces. If the thread is untwisted, it is often seen that it is assembled from different fibers. Using tweezers, sort these fibers into different piles, estimate the percentage and burn each pile separately, forming a ball from each pile or even twisting the threads.

Stop! They forgot about the most important thing! Safety precautions! Before you start experimenting, protect your hair with a headscarf and prepare the room, remove extraneous odors, and eliminate drafts. After burning one thread, ventilate the room, burn the second thread and ventilate the room again. Be sure to place something non-flammable under the material you are burning. Let it be a plate, a baking sheet from the oven or a simple sheet of foil from a chocolate bar. It is not recommended to use matches; they are wooden, and their smell will overwhelm the smell of burnt thread and interfere with the experiment. A candle or a simple lighter will help you. Be sure to have water ready so that you can put out a fire that has gotten out of control in time. Remember that some fibers do not ignite immediately, but once ignited, they become excited and do not want to go out.

You can, of course, test the fibers chemically. For example, in nitric acid (HNO 3) cotton will dissolve and wool will turn yellow. And if you immerse cotton in a 10% solution of caustic soda (NaOH), it will swell, but wool will simply dissolve.

But you are unlikely to do such experiments at home, it is unsafe, and the necessary solutions may simply not be available at home.

From fibrous composition depends on the appearance, elasticity of tissues, cutting resistance, fraying, extensibility, ability to iron and pull back, choice of WTO mode.

Depending on the fibrous composition, fabrics are divided into homogeneous, heterogeneous, mixed and mixed-heterogeneous.

HOMOGENEOUS fabrics consist of the same fibers, for example wool, cotton, silk, etc.

HETEROGENEOUS fabrics consist of thread systems of different types of fiber, for example, warp - cotton, weft-wool; warp - viscose, weft - acetate.

MIXED fabrics are fabrics that contain different fibers in the warp and weft, mixed during the spinning process. For example, the warp and weft are wool with lavsan. Mixed fabrics include fabrics made from twisted, heterogeneous threads.

MIXED-HONOGENEOUS - these are fabrics that have one system of threads that is uniform, and the second from a mixture of fibers. For example, the warp is cotton, and the weft is a mixture of wool with staple viscose fiber. Based on the presence of more valuable fiber, heterogeneous, mixed and mixed-heterogeneous fabrics are usually called half-wool, half-linen, half-silk. Half-silk fabrics usually have a silk warp and a cotton weft. Pure wool fabrics can contain up to 10% chemical fibers.

DETERMINATION OF FIBROUS COMPOSITION OF TISSUE

You can determine the composition of the tissue using the senses: touch, vision, smell in the following sequence:

1. By appearance
2. Touch and wrinkleability
3. By type of warp and weft threads
4. According to the nature of fiber combustion

When determining the fiber composition, first of all, you need to pay attention to the color, gloss, thickness, and density of the fabric. Then work on creasing: gather the fabric into folds and squeeze it tightly in your fist, after 30 seconds release it and smooth it with your hand. Next, consider the warp and weft threads. Each thread must be examined separately. Then trace the combustion pattern of the fibers. Burning tissue with an “angle” leads to erroneous results.

Signs of determining the composition by appearance:

Cotton fabrics are usually thinner than linen; cotton gives them a special dullness, while linen fabrics have a shine. Linen fabrics are often natural color: severe linen fabrics have a grayish or greenish tint. Raw cotton fabrics have a yellowish tint.

Woolen fabrics are recognized by their woolly surface, piled in clothed fabrics and with an open weaving pattern in combed fabrics; The surface of fine cloth fabrics is smooth, while coarse hairs are visible on coarse cloth fabrics. Wool-blend fabrics mixed with cotton are characterized by some fading.

Fabrics made from natural silk are easily recognized by their thin thickness, smooth surface and soft, deep shine.

Based on the nature of creasing and the feel of fabrics, they are determined as follows:

Linen always gives the impression of coldness and rigidity to the touch, cotton - softness and warmth; Linen fabrics, as a rule, are heavier than cotton and have almost no stretch either along the warp or weft.

Pure wool fabrics, when crumpled, either do not form wrinkles, or wrinkles easily disappear; on fabrics mixed with viscose or staple fiber, angular folds remain that do not disappear or disappear slowly.

Fabrics made from natural silk are light, soft to the touch and wrinkle relatively little; fabrics from artificial silk heavier, harsh to the touch and, when crushed, leave folds that are difficult to straighten out.

To determine the composition of the fabric by the type of warp and weft threads, you need to remove 2-3 threads from each system, put them side by side and compare the appearance. If the yarn is twisted, you need to unwind it into separate threads and look through each thread.

Wool is recognized by its peculiar crimp and slight sheen; cotton by its matte, thin, short fibers; staple fiber by its thin, longer, non-crimped fibers with increased shine.

Determination of the fibrous composition by the nature of the rupture of the warp and weft threads:

When a cotton thread breaks, a fluff of short, very thin fibers forms at its end; at the end of a torn linen thread, a tassel is formed from straight, longer, coarser fibers of unequal thickness.

The wool fibers at the broken end of the yarn are recognized by the presence of crimp; if the yarn is mixed (with a mixture of cotton or staple), the cotton differs in its short, thin matte fibers, the staple fibers are long, shiny, as if flaccid.

When a natural silk thread breaks, the individual fibers remain connected, while in threads made from artificial and synthetic fibers, especially with a slight twist, the fibers at the end scatter, forming a fluffy tassel that “sticks to the fingers.”

The strength of natural silk does not change after soaking, the strength of viscose and copper-ammonium fibers after soaking decreases by 50%, and the strength of acetate decreases by 30%.

By the nature of the burning of fibers, the fibrous composition of fabrics can be determined quite accurately:

1. Black yarn sinteres in the flame, but does not burn when removed from the flame. A black cake forms at the end of the thread. The smell of burnt feathers or horn. If wool yarn contains 10% plant impurities, then a luminous ember is formed behind the sintered ball, which quickly goes out, leaving a layer of gray ash. If the yarn contains 15-20% impurities, then 1.5-2 cm of thread burns, then the flame goes out. If the yarn contains more than 25% vegetable impurities, then the entire thread burns out and loose gray ash remains. If wool yarn contains nitron or lavsan, then it burns with a yellow, smoky flame, forming a hard skeleton of the thread, the smell of a feather. If the yarn contains up to 10% nylon, it burns like pure wool, but a ball remains at the end, which does not rub well.
2. Cotton fibers burn with a yellow flame and burn completely, forming gray ash. The smell of burnt paper.
3. Linen burns just like cotton.
4. Natural silk burns similarly to wool.
5. Rayon fibers burn faster than cotton.
6. Acetate fiber burns quickly with a yellow flame, leaving a melted ball at the end.
7. Nylon fibers burn with a bluish flame, forming a brown melted ball.
8. Lavsan melts, then slowly burns with a yellow, smoky flame.
9. Nitron, acrylic (polyacrylonitrile fibers) melt and burn with a yellow flame with flashes.

In the laboratory method of determining the fibrous composition of tissues, microscopes and chemical reagents are used. To determine the composition using this method, you need to have a good knowledge of the structure of the fibers and their chemical properties. The laboratory method gives a more accurate result than the organoleptic one, but in practice it is more often used last method as more accessible.

It is usually not difficult to distinguish synthetic fabric from natural fabric in a store. Just read the composition of the material on the price tag, or ask the seller. In addition, natural fabrics are often much more expensive than synthetics. However, there are quite a lot of situations where the composition of the tissue is unknown. How can you find out what the fabric is made of? Read under the cut.

Serious doubts regarding the composition of the fabric may arise if you buy a piece secondhand, or if you discover large deposits of fabric of unknown origin at home. :) Sometimes I doubt the composition of the fabric even in the store. For example, if the cotton feels too silky or stretchy. Or if it doesn't wrinkle at all.

But why so scrupulously find out the true composition of the material? Firstly, to understand the fabric you have chosen. And secondly, . I am one of them. I feel hot in synthetics, but the worst thing is allergic reactions. Of course, there must be an integrated approach, and nutrition, as well as cosmetics, should also be as natural as possible. But clothing can be a big factor in combating unpleasant skin reactions.

In my opinion, with experience, many fabrics can be identified by touch. For example, natural wool has a very recognizable smell and is easy to recognize by touch. But, of course, you can always run into a very well-made synthetic fabric. How to determine the composition of the fabric? For this we need... Matches or a lighter. Yes, yes, we will check the composition of the fabric this old-fashioned way.

For my experiment I selected:

Viscose lining fabric.

Unnamed fabric, synthetic in my opinion.

Unnamed chiffon, similar to synthetics.

Let's start the experiment. General rule for all natural fabrics: the ashes should be ground into powder. The ashes of mixed fabrics cannot be ground into powder; lumps will still remain between your fingers.

How should wool behave?

The wool curls into a ball and emits the smell of burnt lint.

Result: I admit that wool was the most difficult for me. Since almost all wool was added, this slightly changed the reaction of the fabric to ignition. And, as you can see, the ashes were not ground into powder.

Cotton should burn like paper.

Result: a piece of fabric caught fire like paper, the ashes were perfectly ground into powder. Confirming the composition of the cotton was very simple.

The burning silk should “jump” above the match and not emit any odor.

Everyone knows that fabrics come in different compositions. They can be combined into three groups - natural, non-natural, mixed. Fabrics made from natural fibers are made from natural raw materials - cotton, linen, silk, wool, etc. Likewise, to natural fabrics can be attributed to viscose.

Non-natural fabrics are made from chemically produced fibers - acetate, polyester, nylon, lavsan, nylon, etc. Blended fabrics may contain several fibers of different origins. Thanks to the latest technologies synthetic fabrics do not differ in appearance from natural fabrics, but knowing the composition of the fabric is very important in order to know how the fabric will behave in the product and how to care for it. Today we will talk about how to determine the composition of fabric by burning.

Cotton and linen. Fibers of plant origin. Cotton from the cotton plant, flax from the flax ear. The fibers burn quickly with a bright flame followed by a glow and a small amount of white smoke. After the flames die out, they smolder for a long time, producing dark gray ash and the smell of burnt paper. Flax smolders worse and dies out faster, leaving virtually no ash or pungent odor.

Cotton

Linen

Natural viscose .

They are made from wood, or rather from cellulose, and from it they produce viscose. This fiber has all the properties of cotton, although it is produced chemically; viscose can safely be classified as a natural fabric. So, it burns very quickly. When the flame dies out, it smolders for a very long time, forming a pungent, thick smell of burnt cotton wool, leaving gray smoke and ash that easily crumbles in your hands.

Viscose

Wool and silk. Animal fibers. Wool is produced from the hair of animals, and in the production of silk, threads produced by the silkworm are used. When burned, these fibers behave the same. They burn slowly, the fibers seem to curl up. Silk without a flame goes out immediately. Wool, after fading, does not smolder. The resulting coal can be easily crushed with your fingers. When wool burns, the smell is like burnt hair or feathers; when silk burns, it smells like burnt horn.

Wool

Silk

Synthetic materials. The initial raw materials for production are oil and gas processing materials (types of fibers - polyamide, polyvinyl chloride, polyester, etc.). Obtained chemically. What they have in common is that when they burn, they melt, forming black smoke and an influx, sintering into a lump that cannot be crushed with your fingers after extinguishing. Distribute sour smell synthetics.

Polyester

Acetate and acrylic fabrics. They burn and melt both in the flame and outside the flame. They also leave behind a dark influx and a hard lump. For example, acetate fiber It also dissolves in acetone.

Blended fabrics. They will burn in the same way as the predominant fiber in the composition burns. For example, if the fabric is wool with the addition of lavsan, then it will smell like wool, but the lump will not completely crumble after it fades.

Although we ourselves sometimes do not mind being deceived. In pursuit of a low price, instead of quality materials, we often give preference to cheaper fabrics. At best, such savings result in discomfort when wearing, at worst - allergies and other health problems.

What fabrics should you buy from when building your wardrobe? How to avoid falling for the bait of unscrupulous sellers? Is it possible to determine the composition of a thing without laboratory tests? We talked about this and much more with a candidate of technical sciences specializing in “Technology of textile materials, clothing and knitwear» Galina Skripko on AiF.ru.

It's not cold in winter, it's not hot in summer

Natalya Kozhina, AiF.ru: Galina Alekseevna, what is “healthy clothing”, which in fact should make up our wardrobe?

Galina Skripko: Clothing is considered healthy if the textile material is made from natural raw materials (cotton, wool, flax, natural silk, etc.) or from material with a high content of it.

It is always comfortable to wear such clothes: it is not cold in winter, and not hot in summer, because the material containing natural fibers, has unique property- keep warm for a long time, slowly cooling, and vice versa, keep cool, slowly warming up. Such material does not have a negative effect on the human biofield, since natural fibers are not capable of accumulating static tension. Due to the high breathability and ability of the material to absorb moisture, the clothing becomes hygienic.

N.K. “AiF.ru”: Is it possible to determine good and high-quality fabric only by its price?

G.S.: No. The initial price for the product is determined by the manufacturer, the final price is determined by the distributor. Both focus on consumer demand when determining prices. In this case, less fashion clothes, although of high quality, can be offered to the buyer at a lower price than a branded one made from lower quality raw materials.

Sometimes, in order to increase sales, manufacturers and distributors of textile products directly deceive the buyer by indicating deliberately false information about the fiber composition of the material on the product label or price tag.

N.K. “AiF.ru”: If price is not an indicator, then what factors can help determine the quality of the fabric?

G.S.: Subjectively, the quality of a material can be determined by appearance and touch. Some natural fibers have a characteristic odor. For example, wool has its own smell, it is difficult to describe it, but when we smell it, we remember it. Why does wool smell? Because she has fatliquoring agents, these products have such a specific smell. Cotton smells fresh.

The naturalness of modified fabrics can be determined by external signs difficult even for a professional. Thus, fabric or knitwear made from mercerized cotton (Mercerized cotton is cotton that undergoes alkali treatment. The fiber becomes thinner, shrinks less and is more even) in appearance differs little from material made from polyester cotton-like fiber.

In everyday conditions, to determine the type of clothing fibers, we can recommend a method based on the characteristics of combustion and the characteristic odor of the combustion residues of the fibers. For example, cotton yarn burns quickly, leaving a burnt paper smell; the burnt residue is easily crushed between your fingers. Yarn made from polyester fibers is characterized by rapid attenuation, the burnt residue has the appearance of a solid black ball, and there is no smell. The presence of wool or natural silk in the yarn is determined by the characteristic smell - burnt horn. If the combustion residue does not crumble when rubbed between your fingers, then the yarn contains synthetics.

N.K. “AiF.ru”: Often in a store you can see things made of 100 percent cotton (i.e., identical in composition), but at the same time they will feel completely different to the touch, why? In this case, what fabric should you choose?

G.S.: Everything is correct. Textile materials with the same fiber composition can have different textures. Texture is determined by the density of the fabric and its thickness. The density of the fabric depends on the density and type of weave of the yarn, and the thickness depends on the thickness of the yarn. If speak about cotton fabrics, then their range is very wide: calico, chintz, satin, crepe, cashmere, flannel, flannel, cambric, etc. The thinnest and most expensive fabric is cambric. It is made from fine, tightly spun cotton yarn, which is obtained from high-quality long-staple cotton. When assessing the quality of the fabric or material of the product, you should carefully examine its surface for defects: thickening of the yarn in limited areas, flakiness (the presence of small lumps of tangled fibers on the surface of the fabric), knots, violations in limited areas of the density of the fabric due to vacuum or compaction between the interweaving of threads , the presence of distortions in the direction of the threads, uneven coloring, displacement of the pattern, etc.

Fabric and knitwear, the yarn of which is made from high-grade fiber, has a smooth surface. The denser the material, the less it deforms during use of the product. However, dense material does not mean thick.

W, CO, CVI - designations that are important to know

N.K. "AiF.ru": What fabric should be used when creating a children's wardrobe?

G.S.: The production of children's clothing requires its compliance with sanitary and hygienic rules and regulations (SanPin), according to which children's underwear up to size 32 and hosiery up to size 16 should not contain synthetic fibers. It is allowed to replace part of the cotton with artificial fiber - viscose:
- up to 10%, for toddler underwear (up to size 28) and hosiery up to size 16;
- up to 30%, for children's underwear up to size 32.

N.K. “AiF.ru”: What fabric composition is ideal for underwear and swimwear?

G.S.: Underwear made from 100% cotton jersey is considered ideal. To increase the elasticity of knitwear, it is permissible to add elastic thread (elastane, spandex) to the yarn, the content of which should not exceed 2-1%. Underwear made from such knitwear is not only hygienic, but also more comfortable, as it fits tightly to the body.

N.K. “AiF.ru”: Galina Alekseevna, please tell us about the symbols that are often used on labels, what do they mean?

G.S.: The designation of raw materials must contain the full name of the types of fibers or their abbreviated designation. The abbreviated designation is mainly used by foreign manufacturers. For example, cotton (cotton) - CO, ALG; flax (flax) - Li; wool (wool) - W or WP, WL, WA (alpaca, llama, angora wool): silk (silk) - SE. For artificial chemical fibers the following designations are used: viscose (viskose) - Vis, VI; high-modulus fiber (Siblon, Modal) - CVI, MD; acetate - AC. Synthetic fibers designate: polyester (polyester) - PE, PE, PES, PL; polyacrylonitrile (acrylic) - PAN, PAC, RS; polyamide (polyamide) - PA, RA; polyurethane (polyurethane, elastane) - PU, PU, ​​EA.

In duplicated canvases, the composition of the raw material is indicated separately for each layer.

When secondary raw materials are included in the material, the words “recycled raw materials” and its type must be indicated.